The present invention relates generally to an apparatus and method for operating a take-up mechanism. Although described and illustrated in the context of a take-up mechanism for a locomotive braking system, one of ordinary skill in the art should appreciate that the present invention may be used to operate any take-up mechanism used to set and release force.
A locomotive is a relatively heavy vehicle conveyed on tracks by wheels. Uncontrolled or inadvertent movement of the locomotive may result in serious injury or damage to adjacent locomotives, railcars, people, or any other item in the path of movement. Therefore, the rail industry requires that all locomotives have a brake system for preventing uncontrolled or inadvertent movement.
Locomotives typically use a parking brake for holding the locomotive for extended periods. The parking brake generally includes a brake surface, such as brake shoes or disks, that can be applied to the locomotive wheels to slow or stop the locomotive. An actuating mechanism connects to the brake surface to set and release the parking brake. The actuating mechanism may include a manual and/or a motorized input device to set and release the parking brake. The manual input device may be a lever or a hand wheel that connects to a ratcheted drive shaft, and a chain or cable may connect the ratcheted drive shaft to the brake surface. In this manner, the ratcheted drive shaft may rotate in one direction to set the parking brake. A release mechanism may disengage the ratchet from the drive shaft to allow the drive shaft to freely rotate to release the parking brake.
Operation of the manual input device and release mechanism requires the operator to be physically present at the parking brake to both set and release the parking brake. In addition, substantial effort and agility are required to properly set and release the parking brake. As a result, some operators are not able to manually operate the parking brake without risking or incurring physical injuries and strains. Moreover, an injured operator may be unable to manually operate the parking brake in an emergency.
U.S. Pat. No. 6,039,158 describes a system for operating a locomotive parking brake that includes both a manual and motorized input device to set the parking brake. The manual input device is a lever or hand wheel that rotates a drive shaft to set the parking brake, and the motorized input device includes a motor to rotate the drive shaft to set the parking brake, as previously described. The motorized input device may further include a motor controller located remote from the parking brake. In this manner, the operator may set the parking brake locally using either the manual or motorized input device. In addition, the operator may set the parking brake remotely using the motor controller. However, the operator must still manually operate a separate release lever located on the system to release the parking brake. As a result, the parking brake can only be released manually by the operator at the parking brake, and the inconvenience and potential for injury still exists.
U.S. Pat. No. 6,913,325 describes a system for operating a vehicle parking brake that includes both a hand wheel and a motor to operate the parking brake. In contrast to U.S. Pat. No. 6,039,158, the operator can both set and release the parking brake locally or remotely from the system using the motor. Alternately, the operator can reposition a lever on the system to disengage the motor and engage the hand wheel to both set and release the parking brake manually. Although the system described in U.S. Pat. No. 6,913,325 provides for both manual and motorized operation of the parking brake, the operator must still manually reposition the lever on the system to switch between manual operation and motorized operation. As a result, motorized and/or remote operation of the parking brake is not possible if the lever is left in the manual position.
Therefore, the need exists for an apparatus and method to operate a take-up mechanism both locally and remotely without requiring any adjustment to the mechanism to allow local or remote operation.